Performance Evaluation of Three-Phase Five-Level Boosted ANPC Inverter Under Different Unipolar PWM Strategy

Abstract

The multilevel inverters (MLIs) with inherent voltage boosting capability are suitable for renewable energy applications. The ANPC inverter topology is better than diode clamped NPC in terms of loss distribution. The five-level boost ANPC (5L-BANPC) topology using same switch count as that of 3LANPC is very promising for photovoltaic application. Besides five level output, 1.7 times voltage boosting is achieved for such 5L-BANPC. The performances of such 5L-BANPC inverter are evaluated concerning peak amplitude of fundamental output voltage, harmonics in the output waveforms, magnitude of common mode voltage and neutral point potential both under different unipolar CBPWM schemes like SPWM (USPWM), unipolar 60° PWM, unipolar third-harmonic injection PWM (UTHIPWM), unipolar Zero-sequence injection PWM (UZSPWM). The 5L-BANPC inverter topology exhibits superior performances under THIPWM in terms of highest peak value of fundamental voltage and lowest THD value. The neutral point potential balancing of the 5L-BANPC topology becomes superior under ZSPWM. The MATLAB/Simulink environment is used for simulation purpose followed by test conducted through hardware-in-loop (HIL) using OPAL-RT simulator.